Equipment Questions, Straight Answers

Sometimes physically, rarely wisely. Mismatched coils cost capacity and efficiency, can void the AHRI match and rebate paperwork, and with the R-454B transition the refrigerant usually won't even line up. Quote the matched system; explain it as protecting the compressor's warranty.

Venting. An 80% breathes through existing metal B-vent; a 96% wants PVC out the sidewall plus a condensate drain. In a retrofit where the venting path is ugly, the install cost difference can eat a decade of gas savings. In propane country the math tilts back toward 96% — LP is expensive fuel.

Down for cooling-dominated homes, up only when heating drives the design and you've got cold-climate equipment. Oversized cooling short-cycles, dehumidifies badly, and wears parts. The load calc is the answer; the bigger box is the temptation.

Check the easy stuff in order: failing run capacitor, then compressor locked-rotor draw on start. A hard-start kit can rescue a marginal compressor on long rural power runs — but if the compressor is grounding out, no kit saves it. Confirm with a megohm check before promising miracles.

Yes. A TXV holds superheat across varying conditions, protecting the compressor and keeping capacity honest in our swing seasons. Fixed orifices are fine when everything matches the design day; mountain weather rarely does. Most current matched systems ship TXV anyway.

Sized to the heating load the heat pump can't cover at design temperature — not 'the biggest kit that fits.' Valley homes often live fine on 5–8 kW; high-elevation homes need more. Oversized strips just slam the panel and the bill. The load calc and the panel's capacity make the call.

Airflow or charge, almost always. Dirty filter, dead blower, crushed flex, or a coil matted with dog hair starve the evaporator; low charge does the same math. Thaw it fully, fix the airflow first, then check charge — icing that returns after both is TXV territory.